The technique of laser reference stars is an integral part of modern adaptive optical systems of ground-based telescopes. The requirements for the energy, spectral, and spatiotemporal characteristics of a laser beam for creating sodium laser guide star, as well as for the adaptive optical system as a whole, are largely related to the atmospheric parameters of telescope site. One aspect of optimizing the brightness of a sodium laser guide star is the choice of linewidth of the laser. In this work, based on numerical simulation of the interaction of laser radiation with mesospheric sodium atoms under the conditions of midlatitude atmosphere in the Russian Federation, the effect of laser bandwidth on the magnitude of the return photon flux from a sodium laser guide star is estimated to determine the requirements for the parameters of the laser. Results are presented for laser radiation with circular polarizations and linewidths from 10 MHz to 3.5 GHz.
laser guide star, adaptive optics, atmospheric turbulence, telescope, astroclimate
1. Bustos P.F., Holzlöhner R., Rochester S., Bonaccini D., Hellemeier J., Budker D. Frequency chirped continuous-wave sodium laser guide stars: Modeling and optimization // J. Opt. Soc. Am. B. 2020. V. 37. P. 1208–1218. DOI: 10.1364/JOSAB.389007.
2. Hellemeier J., Enderlein M., Hager M., Bonaccini Calia D., Johnson R.L., Lison F., Byrd M.O., Kann L.A., Centrone M., Hickson P. Laser guide star return-flux gain from frequency chirping // Mon. Not. Roy. Astron. Soc. 2022. V. 511, N 3. P. 4660–4668. DOI: 10.1093/mnras/stac343.
3. Rochester S.M., Otarola A., Boyer C., Budker D., Ellerbroek B., Holzlöhner R., Wang L. Modeling of pulsed-laser guide stars for the Thirty Meter Telescope project // J. Opt. Soc. Am. B. 2012. V. 29. P. 2176–2188. DOI: 10.1364/JOSAB.29.002176.
4. Holzlöhner R., Bonaccini D., Bello D., Budker D., Centrone M., Guidolin I., Hackenberg W., Lewis S., Lombardi G., Montilla I., Pedichini F., Pedreros Bustos F., Pfrommer T., Reyes Garcia Talavera M., Rochester S. Comparison between observation and simulation of sodium LGS return flux with a 20W CW laser on Tenerife // Proc. SPIE. 2016. V. 9909. P. 99095E–8. DOI: 10.1117/12.2233072.
5. Kleimyonov V.V., Novikova E.V., Oleinikov M.I. O vybore diametra apertury zondiruyushchego lazera v nazemnyx adaptivnyx optiko-elektronnyx sistemax pri formirovanii natrievoi opornoi zvezdy // Nauchno-texnicheskii vestnik informatsionnyx texnologii, mexaniki i optiki. 2021. V. 21, N 1. P. 24–30. DOI: 10.17586/2226-1494-2021-21-1-24-30.
6. Martinez N., D’Orgeville C., Grosse D., Lingham M., Webb J., Copeland M., Galla A., Hart J., Price I., Schofield W., Thorn E., Smith C., Gao Y., Wang Y., Blundell M., Chan A., Gray A., Fetzer G., Rako S. Debris collision mitigation from the ground using laser guide star adaptive optics at mount Stromlo observatory // J. Space Saf. Eng. 2022. V. 9, N 1. P. 106–113. DOI: 10.1016/j.jsse.2021.10.007.
7. Kleimyonov V.V., Vozmishchev I.Yu., Novikova E.V. Effektivnost' primeneniya monostaticheskoi sxemy formirovaniya lazernoi opornoi zvezdy // Opt. zhurn. 2022. V. 89, N 11. P. 24–31. DOI: 10.17586/1023-5086-2022-89-11-24-31.
8. Rui-Tao Wang, Hong-Yang Li, Lu Feng, Min Li, Qi Bian, Jun-Wei Zuo, Kai Jin, Chen Wang, Yue Liang, Ming Wang. First Sodium Laser Guide Star Asterism Launching Platform in China on the 1.8 m Telescope at Gaomeigu Observatory // Publ. Astron. Soc. Pacif. 2023. V. 135, N 1045. P. 034502. DOI: 10.1088/1538-3873/acbe68.
9. Bol'basova L.A., Ermakov S.A., Lukin V.P. Modelirovanie yarkosti natrievoi LOZ, formiruemoi polyarizovannym izlucheniem, dlya astronomicheskix observatorii Severnogo Kavkaza // Optika atmosf. i okeana. 2023. V. 36, N 9. P. 773–779. DOI: 10.15372/AOO20230909; Bolbasova L.A., Ermakov S.A., Lukin V.P. Simulation of return flux of sodium LGS generated by polarized light for astronomical observatories of the North Caucasus // Atmos. Ocean. Opt. 2023. V. 36, N S1. P. S94–S100. DOI: 10.1134/S1024856024010056.
10. Xiaowei Huo, Yaoyao Qi, Yu Zhang, Bin Chen, Zhenxu Bai, Jie Ding, Yulei Wang, Zhiwei Lu. Research development of 589 nm laser for sodium laser guide stars // Opt. Laser. Eng. 2020. V. 134. P. 106207–10627. DOI: 10.1016/j.optlaseng.2020.106207.
11. Yunpeng Cai, Jie Ding, Zhenxu Bai, Yaoyao Qi, Yulei Wang, Zhiwei Lu. Recent progress in yellow laser: Principles, status and perspectives // Opt. Laser. Eng. 2022. V. 152. P. 108113–108130. DOI: 10.1016/j.optlastec.2022.108113.
12. Pengbo Jiang, Xin Ding, Jian Guo, Haiwei Zhang, Haifeng Qi, Ying Shang, Zhiqiang Song, Weitao Wang, Chen Wang, Guangqiang Liu, Chunmei Yao, Jiasheng Ni, Jianquan Yao. Research progress of crystalline Raman yellow lasers // Opt. Laser Technol. 2024. V. 169. P. 110072. Р. 1–15. DOI: 10.1016/j.optlastec.2023.110072.
13. Pique J.-P., Farinotti S. Efficient modeless laser for a mesospheric sodium laser guide star // J. Opt. Soc. Am. B. 2003. V. 20. P. 2093–2101. DOI: 10.1364/JOSAB.20.002093.
14. Liu X., Qian X., He R., Liu D., Cui C., Fan C., Yuan H. Effects of linewidth broadening method on recoil of sodium laser guide star // Atmosphere. 2021. V. 12. P. 1315-1–17. DOI: 10.3390/atmos12101315
15. Holzlöhner R., Rochester S.M., Bonaccini Calia D., Budker D., Higbie J.M., Hackenberg W. Optimization of CW sodium laser guide star efficiency // Astron. Astrophys. 2010. V. 510. DOI: 10.1051/0004-6361/200913108.
16. Rochester S. Atomic Density Matrix package for Mathematica, LGSBloch package for Mathematica. URL: https://rochesterscientific.com/ADM/ (last access: 20.12.2023).
17. Rampy R., Gavel D., Rochester S.M., Holzlöhner R. Toward optimization of pulsed sodium laser guide stars // J. Opt. Soc. Am. B 2015. V. 32. P. 2425–2434. DOI: 10.1364/JOSAB.32.002425.
18. GOST R ISO 13695-2010 Optika i fotonika. Lazery i lazernye ustanovki (sistemy). Metody izmerenii spektral'nyx xarakteristik lazerov. M.: Standartinform, 2011. 22 p.
19. Milonni P.W., Fugate R.Q., Telle J. Analysis of measured photon returns from sodium beacons // J. Opt. Soc. Am. A. 1998. V. 15. P. 217–233. DOI: 10.1364/JOSAA.15.000217.
20. Moussaoui N., Holzlöhner R., Hackenberg W., Bonaccini Calia D. Dependence of sodium laser guide star photon return on the geomagnetic field // Astron. Astrophys. 2009. V. 501, N 2. P. 793–799. DOI: 10.1051/0004-6361/200811411.
21. Li Lihang, Hongyan Wang, Weihong Hua, Yu Ning, Xiaojun Xu. Fluoreenhancing mechanism of optical repumping in sodium atoms for brighter laser guide star // Opt. Express. 2016. V. 24. P. 6976–6984. DOI: 10.1364/OE.24.006976.